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Vehicle Hydropneumatic Unit
Koudelka, Roman ; Hejtmánek, Petr (referee) ; Blaťák, Ondřej (advisor)
This diploma thesis, following the bachelor's thesis, is devoted to the gas-liquid unit of a vehicle, as the central element of hydropneumatic suspension. The aim is to dimension and construct this component and integrate it together with other elements into a complex suspension system. Based on possible forms listed in the research section, regarding to current development trends, the form of the unit is chosen. The practical part begins with simulations comparing a hydropneumatic with a conventional suspension system. After solving this issue, it is possible to proceed to the dimensioning of the basic parameters of the unit and then to its construction, respecting the relevant strength calculations. The last step is to build a conceptual design of the whole hydropneumatic suspension system.
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The modal damping ratio analysis of the mechanical part using the OMA method
Sodomka, Tomáš ; Lošák, Petr (referee) ; Houfek, Lubomír (advisor)
In one of the first hours of study at the Institute of Mechanics of Bodies, Mechatronics and Biomechanics, the author of this work received three basic recommendations regarding measurement: 1) Do not measure! 2) If you measure, do not repeat the measurement!! 3) If you repeat the measurement, do not compare the measurements!!! However, this thesis boldly violates all three recommendations. In the introductory theoretical part, it briefly introduces the vibration of multi-degree of freedom damped systems and describes experimental ways of determining the modal damping. It also summarizes the Operational Modal Analysis (OMA) approach, explains the principle of the FDD method, and introduces EFDD (Enhanced Frequency Domain Decomposition) method which allows to determine not only natural frequencies and shapes as FDD does, but also modal damping of the shapes. A script in Matlab environment for processing vibrations using EFDD method is one of the thesis outputs. The script is first tested by computational model, where a model system with known damping is tested and damping is determined by the script. Subsequently, the work moves to the actual measurement of the real system - a bonded bar which is analysed by Experimental Modal Analysis and OMA, while the second variant uses commercial EFDD method (Brüel a Kjr company) and programmed script. In the conclusion of the thesis the damping results are compared to each other. The diploma thesis continues in Ing. M. Pop’s thesis – Modal Analysis Experimental Method Verification. From this work a part of measured data is taken. Specific cases of data use are always listed in the appropriate section of the text.
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Development of transaxles in automobiles
Kubiš, Vojtěch ; Kaplan, Zdeněk (referee) ; Píštěk, Václav (advisor)
This bachelor thesis is concerned of development of transaxles in automobiles. Overview of types of axles is mentioned here as well as their working principles. Attention is also given to suspension and damping with description of how it works. In this thesis are described solutions of selected cars suspensions.
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Effect of Shock Absorber on Vehicle Limits
Jurka, Adam ; Blaťák, Ondřej (referee) ; Hejtmánek, Petr (advisor)
The aim of this master’s thesis is to evaluate the effect of shock absorber on vehicle limits. At the beginning of the thesis, shock absorber properties were described. Then computational model was created and manoeuvres for shock absorber behaviour were defined. Created mathematical model is based on quarter model of a car and excitation in form of road with a random profile is an essential part of the model. This model was used for evaluation of heave. After heave analysis, shock absorber behaviour during drive was investigated. Drive conditions were defined as set of handling manoeuvres. For the drive investigation, complete multibody virtual model of racing car was used. Based on drive investigation analysis, optimal damping characteristics for each manoeuvre were found. Furthermore, each optimal characteristic was compared for different manoeuvres. Obtained results were compared. As a conclusion, compromise damping characteristic was suggested with the aim to fit the combination of all defined drive conditions. Final part of the thesis was aimed at validation of the computational model. Data measured during real drive were used as an input for this validation.
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Design of optical amplifier
Somora, Rastislav ; Číž, Radim (referee) ; Slavíček, Karel (advisor)
This Bachelor's thesis deals with design and construction of support circuits for a modern optical amplifier the SOA. In the first chapter, optical transmitting medium with its physical properties and types of used cabels is described. The overview includes a list of optical cables, their damping properties and parasitic effects which can occur durring comunication. Next chapter is focused on the optical signal sources used in modern data networks, describes their internal structure and physical essence. Third chapter is dedicated to designing the optical amplifier with the SOA circuit. It focuses on the right choice of parts, their arrangement and layout of the design. Last chapter deals with set up, calibration and control of the optical amplifier module.
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Resonance and damping behavior of lattice structures produced by Selective Laser Melting
Lagiň, Adam ; Čížek, Petr (referee) ; Koutný, Daniel (advisor)
In reaction to the uptrend of additive manufacturing of lightweight structured metallic parts, this diploma thesis is focused on the resonant and damping behavior of micro-truss lattices produced by Selective Laser Melting (SLM) technology. Micro-truss structures already found usage in various types of optimizations. Therefore, the optimization of resonance or damping could be also assumed as possible. For this purpose, several finite element analysis approaches were used, including the referent solid element model and simplified beam models. Obtained results were verified experimentally via pulse modal analysis. Material and mechanical properties of samples for FEA results and experimental results comparison were unified through secondary experiments. The main goal of this research was to explore the behavior of resonance and damping of structures when their elementary parameters are changed. The results from both, numerical and experimental approaches confirm that the eigenfrequency and the damping ratio of the structure can be affected by the change in the truss diameter, cell size, or type of structure. The work also presents the successful methods for simplified beam model optimization, which guarantees its high precision in the wide field of tested samples. This newly obtained knowledge creates a comprehensive overview of micro-truss structures, which can be used for the conscious design of ultra-light parts with the required eigenfrequency and damping ratio.
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Design of semiconductor optical amplifier
Somora, Rastislav ; Hanák, Pavel (referee) ; Slavíček, Karel (advisor)
Diploma thesis deals with the construction of a moder semiconductor optical amplifier SOA. In the first chapter optical comunication and the use of optical amplifiers is described. In the next chapter some types of optical fibers, their chemical composition and properties are described in detail. The third chapter overviews optical amplifiers, their use today, describes their advantages and disadvantages and their proper use in optical comunications. The fourth chapter describes the solution of the objective, the right layout of separate blocks and connections used in measurements. Fifth chapter describes used components, describes their basic parameters and proper use in circuit. The last chapter evaluates outputs of measurements and their impact on the objective.
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Analysis of Smart Materials
Rašner, Martin ; Lošák, Petr (referee) ; Hadaš, Zdeněk (advisor)
The bachelor's thesis "Smart Materials Analysis" deals with the description of intelligent materials in the way of usability in technical practice. At first, the research of smart materials is carried out, which is further elaborated on a detailed description of shape memory materials. In order to investigate the functionality of the material and the description of its behaviour in terms of non-linear oscillation, a simplified model is proposed. The practical part deals with the application of passive damping of Nitinol. The solution is accomplished by modelling program MATLAB / Simulink.
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Dynamic analysis of structure loaded seismic loads
Šulerová, Zdeňka ; Nevařil, Aleš (referee) ; Vlk, Zbyněk (advisor)
This thesis deals with the calculation of response of reinforced concrete construction on the effect of seismic tension. Time and spectral analysis were made. They are mentioned as possible ways of calculation in EN 1998 - 1:2004 norm. Final figures of global deformations and stress on selected beam from the time and spectral analysis were firstly compared for the horizontal components of seismic stress affecting only in one direction. Subsequently comparison of time progress to combination of these effects mentioned in relevant norm was made. In the conclusion the results of used analysis are appraised.
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